1. Field of the Invention
The present invention relates generally to a two-way communications earpiece for use with a hearing aid.
2. State of the Art
Conventional two-way communications gear such as headsets and telephone handsets can present difficulties when used with hearing aids. In particular, the portion of the headset or telephone handset that rests against a user""s ear can create a closed volume that reflects any sound leaking out of the user""s ear from the hearing aid, back to the hearing aid microphone. An unpleasant positive feedback situation quickly develops which degrades the effectiveness of the hearing aid and can make conversation impossible.
Furthermore, cell phones can generate amplitude-modulated signals that interfere with hearing aids. For example, cell phones that employ the GSM standard commonly used in Europe, communicate with base stations at radio frequencies using digital signals. The communications are typically performed using time-division-multiple access (TDMA) protocols, so that the cell phone periodically transmits data in digital form over a radio frequency (RF) carrier wave. Between time slots, the carrier wave is turned off. The repetition frequency of the time slots can be on the order of about 220 Hz. In other words, even though the carrier wave is at a radio frequency and carries digital information, it is turned on and off at about 220 Hz and thus constitutes an amplitude modulated signal having a fundamental frequency of about 220 Hz. The radio frequency of the cell phone carrier wave is typically high enough that electrical components and lines within the hearing aid act as antennae and receive the carrier wave when the cell phone is close to the hearing aid, for example pressed against the user""s ear. Circuit components within the hearing aid rectify the carrier wave and unintentionally recover the modulation. Although the electrical noise generated in the hearing aid by this unintended reception is small in magnitude, it can occur in the early, pre-gain stages of the hearing aid and thus be substantially amplified by the time it passes through the gain stages and appears at the output, for example a speaker, of the hearing aid. In this way a cell phone can introduce noise having a fundamental frequency of about 220 Hz into the hearing aid, and that frequency plus its harmonics are well within the frequency range of the human ear, which can significantly interfere with the user""s ability to understand speech or other sounds relayed by the hearing aid.
In addition to the RF pulses radiated by the GSM cell phones and other cell phones using similar RF methods, the act of turning the RF transmitter on and off causes the current drawn by the cell phone circuitry to pulse up and down at the same rate that the transmitter is turned on and off. This generates magnetic pulses. If a cell phone of this type is held to the ear of a user wearing a hearing aid equipped with a pickup telecoil, then the telecoil will detect the magnetic pulses. The resulting signal from the telecoil pickup is large enough that it can render the hearing aid unusable in this mode, even if the hearing aid is shielded against the RF pulses.
U.S. Pat. No. 5,796,821 to Crouch, et al. (Crouch) discloses a hearing aid telephone interconnect system (HATIS) that provides an output audio electronic signal originally intended for a speaker in a telephone handset, stereo sound system, television set, etc. to a coil in a xe2x80x9cT-couplerxe2x80x9d device located near a user""s pickup telecoil-equipped hearing aid. The T-coupler includes a coil. Based on the electronic signals, the coil generates electromagnetic waves in the audio frequency spectrum. The pickup telecoil in the hearing aid receives the electromagnetic signal generated by the coil, and the hearing aid uses the received signal to provide a corresponding acoustic signal to the user.
U.S. Pat. No. 5,761,319 to Dar, et al. (Dar) discloses an instrument for augmenting the versatility of an in-the-ear (ITE) hearing aid or a completely-in-the-canal (CIC) hearing aid. In particular, Dar discloses an instrument mounted behind the ear and including a receiver for receiving wireless signals, an electroacoustic transducer for generating acoustic sound signals corresponding to the wireless signals, and a tube that is positioned near the hearing aid to convey the acoustic sound signals to a microphone or acoustic pick up port of the in-the-ear hearing aid.
The present invention accurately and efficiently relays incoming signals to a hearing aid from a two-way communications device, such as a cell phone, without inducing electronic interference or acoustic feedback. An exemplary embodiment of the invention includes an earpiece having a breakaway mount for attaching the earpiece directly to a hearing aid worn by a user, and an acoustic tube that conveys sound from a speaker in the earpiece to an acoustic aperture in an outer housing of the hearing aid. The breakaway mount can accurately position the acoustic tube near an acoustic pickup of the hearing aid, such as an acoustic aperture that directs acoustic sound to a microphone within the hearing aid, so that the acoustic tube can efficiently provide acoustic sound signals to the hearing aid. The earpiece can also include a microphone for picking up the user""s voice and surrounding sounds, and relaying corresponding signals back to the two-way communications device.
The breakaway mount allows the earpiece to be mounted on a variety of hearing aids including in-the-ear (ITE), in-the-canal (ITC), and behind-the-ear (BTE) hearing aids. The earpiece can break away from the hearing aid when force is applied to the earpiece, so that force will not be transferred to the hearing aid and potentially injure the user. The earpiece can also be quickly and easily mounted on, or dismounted from, the hearing aid by the hearing aid wearer depending on the wearer""s particular needs at any given time. For example, the hearing aid wearer can easily mount the earpiece on, or easily dismount the earpiece from, the hearing aid while wearing the hearing aid.
Some hearing aids are provided with a pickup telecoil, which can receive sound in the form of electromagnetic waves in the audio frequency spectrum. To take advantage of this feature, an exemplary embodiment of the earpiece is provided with a transmitter telecoil that is connected to a transceiver within the earpiece. The earpiece transceiver can then drive the transmitter telecoil to generate electromagnetic waves in the audio frequency spectrum, which are received by the pickup telecoil in the hearing aid. Thus, the earpiece can provide an electronic sound signal directly to the hearing aid via an electromagnetic link between the transmitter telecoil in the earpiece and the pickup telecoil in the hearing aid. The electronic sound signal provided by the transmitter coil can either accompany or replace the acoustic sound signal conveyed by the acoustic tube to the hearing aid. When both are provided, the hearing aid user can control whichever signal is desired using the standard microphone/telecoil switching function provided in telecoil equipped hearing aids. Unlike the HATIS device, the earpiece also includes an acoustic microphone that picks up sounds ambient to the earpiece, such as the user""s voice, and can provide the microphone output signal to the transceiver so that the sounds picked up by the microphone can be transmitted or conveyed to a remote device. The remote device can be the same device from which the transceiver is receiving signals for transfer to the hearing aid via the transmitter telecoil in the earpiece and the pickup telecoil in the hearing aid. The remote device can be, for example, a cell phone.
Generally speaking, exemplary embodiments of the invention relate to a two-way communications earpiece for use with a hearing aid, including a microphone for picking up sounds ambient to the earpiece, an acoustic tube for providing acoustic sound to a microphone in the hearing aid, and a mount for detachably mounting and orienting the earpiece on the hearing aid so that when the earpiece is mounted on the hearing aid, an end of the acoustic tube is near the hearing aid microphone and the acoustic tube can convey acoustic sound generated by the transducer in the earpiece to at least one of an acoustic aperture and a microphone in the hearing aid, while leaving the hearing aid microphone unobstructed to ambient sounds.